1. Field of the Invention:
The invention is directed to a seed tube having an internal ramp like structure located immediately above the forward sensor aperture to prevent falling seeds from interfering with the operation of the sensor.
2. Description of the Prior Art:
Agricultural seeding machines are typically provided with a seed meter and a furrow opener between which extends a seed tube. The seed meter measures the amount of seed to be directed to the planting furrow formed by the furrow opener. The seed tube transports the seed from the seed meter to the planting furrow formed by the furrow opener.
A typical seed tube is illustrated in U.S. Pat. No. 4,915,258. The tube illustrated in this patent comprises a forward wall and a rear wall which are joined together by sidewalls forming a hollow tube. The forward and rear walls are curved rearwardly. As the seed is dropped from the seed meter it runs down the inside surface of the forward wall into the planting furrow.
To insure that the planting unit is operating correctly, the seed tube maybe provided with a seed sensor. A typical seed sensor is marketed by Dickey-john Corporation of Auburn, Illinois. The sensor components of the seed sensor are mounted to the front and rear walls of the seed tube. The front wall is provided with a sensor aperture and the rear wall is provided with a second sensor aperture. A light is projected from a light source located in the second sensor aperture of the rear wall across the seed tube to a light receiver located in the sensor aperture of the forward wall. Whenever a seed passes between the light source and the light receiver, the seed interrupts the light beam and the seed is detected.
The light source and light receiver are designed to extend into the apertures and be substantially even with the interior surfaces of the front and rear walls. Sometimes the sensor may extend past the interior surface of the front wall. In this situation the seed hits the top edge of the sensor and where the seed can be damaged. In addition, and its trajectory into the planting furrow would be affected.